Tool holder and method of using

ABSTRACT

The specification discloses a tool holder, especially for receiving throw away inserts in which the tool holder is a barlike member adapted for being clamped in a tool support member. The bar-like member has abutment elements thereon to abut the support member to locate the tool holder in a predetermined position. The regions for receiving the abutments are threaded for receiving threaded abutment screws and are adapted at their outer ends to receive pressed in abutment elements which can be ground to a precise dimension whereby the mounting of the tool holder in the support member will provide for precise fixed positioning of an insert mounted on the holder.

United States Patent Kennicott etal.

[ 1 Oct. 3, 1972 TOOL HOLDER AND METHOD OF USING [72] Inventors: WilburL. Kennicott, Ligonier; James W. Heaton, Greensburg, both I of Pa.

[73] Assignee: Kennametal lnc., Latrobe, Pa.

[22] Filed: Sept. 28, 1970 211 Appl. No.: 75,873

Primary Examiner-Harrison L. Hinson Attorney-Melvin A. Crosby [57]ABSTRACT The specification discloses a tool holder, especially for [52]U.S. Cl ..29/96 receiving throw away inserts in which the tool holder[51] Int. Cl. ..B26d 1/00, B23b 29/00 s a bar-like member adapted forbeing clamped in a [58] Field of Search ..29/96, 97, 98, 105, 105 A;tool pp member. The bar-like member h abut- 2/30 ment elements thereonto abut the support member to locate the tool holder in a predeterminedposition. [56] R f c Cited The regions for receiving the abutments arethreaded for receiving threaded abutment screws and are UNITED STATESPATENTS adapted at their outer ends to receive pressed in abutmentelements which can be ground to a precise 233232 3 g dimension wherebythe mounting of the tool holder in l 6 mo 29 96 the support member willprovide for precise fixed wifii 4 positioning of an insert mounted onthe holder. 1 rams 3,252,202 5/1966 Bullard ..29/96 6 Claims, 5 DrawingFigures l4 l2 II k 36 '8 1 I 'l 5 1' .I A

TOOL HOLDER AND METHOD OF USING The present invention relates to toolholders and to methods of making and using tool holders and isparticularly concerned with tool holders of the present type, especiallythose adapted for receiving throw away inserts.

Tool holders are well-known in the trade and usually take the form ofsome sort of shank member adapted for being clamped in a support on amachine tool and having a hard cutting insert mounted thereon forengagement with the work being operated in the machine tool. The hardinserts can be cemented or brazed in place on the holder but usually areof the throw away type which are manufactured to precise dimensions.

An ever increasing number of machine tools are numerically controlledaccording to programs recorded on punched tape, or the like, and, inconnection with such machine tools, it is desirable to be able toposition an insert in a very precise position in the machine toolrelative to the work so that the workpiece operated thereby will comeout to exactly the desired dimensions.

Even in instances where machine tools are not numerically controlled,as, for example, with a template controlled machine tool, it isdesirable for the cutting edge on the cutting insert to occupy a certainprecise position in the machine tool. v

l-leretofore, it has been customary to provide the shanks on which suchcutting inserts are mounted with abutment elements which engageaccurately located surfaces in the support member in the machine toolprovided to receive the holders whereby the abutment elements determinethe exact position of the cutting edge of the insert. The aforementionedabutment elements are generally threaded into the shank of the toolholder and can be adjusted therein by means of a suitable fixture beforethe shank is mounted in the support member so that the operation ofchanging tools can be quickly carried out by the tool operator.

In certain instances, as, for example, for numerically controlledmachine tools, the degree of precision required for the cutting edge ofthe insert is such that the surfaces of the shank of the tool holder areground relative to the cutting edge of the insert. The ground area onthe holder is engaged with a ground area on the support provided for theholder in the machine tool and the holder is then firmly clamped. Theprocedure eliminates all possibility of error or improper setting ofadjustable abutment elements, but does not allow for variations frominsert to insert and is not, therefore, always accurate enough.

l-leretofore, the holders having fixed ground abutment areas thereonwere an individual type of holder and those having adjustable abutmentelements therein were a different type thus requiring that both toolmanufacturers and users maintain an inventory of both types of holdersand substantially Preventing the use of either type holder incircumstances dictating the use of the other type holder.

With the foregoing in mind, a primary objective of the present inventionis the provision of a holder for a cutting insert so constructed andarranged that it can be employed either with adjustable abutmentelements, or areas, or with fixed ground abutment elements, or

areas.

A still further object is the provision of a holder of the naturereferred to which can readily be converted from one type to the other.

Still another object of this invention is the provision of a method ofconstructing and using tool holders of the nature referred to whichpermits the advantages of both type of holders identified above to berealized in one and the same holder.

These and other objects and advantages of the present invention willbecome more apparent upon reference to the following detailedspecification taken in connection with the accompanying drawings inwhich:

FIG. 1 is a plan view showing a holder according to the presentinvention mounted in a pocket in a support member therefor;

FIG. 2 is a view looking in at the side of the tool holder;

FIG. 3 is a fragmentary sectional view showing a typical knurlingpattern employed on a plug forming a part of the present invention andadapted to be pressed into a holder;

FIG. 4 is a perspective view showing the knurled plug; and

FIG. 5 is a fragmentary view showing another manner in which a pressedin plug could be provided for a holder according to the presentinvention.

Referring to the drawings somewhat more in detail, in FIG. 1, 10represents a tool support member of a machine tool having a pocket 12for receiving a tool holder generally indicated at 14. Too] holder 14comprises a shank portion 16 within pocket 12 and a pro jecting portion18 having a pocket in which a cutting insert 20 is detachably mounted asby being clamped in place in the holder pocket by a chip breaker 22 anda hold down clamp 24.

The shank portion 16 of the tool holder is clamped in place in thepocket by any suitable clamping means and comprises abutment elements 26in spaced relation along one side of the tool holder and abutmentelement 28 at the back end of the tool holder. The abutment elementsengage accurately located surfaces in pocket 12 and thereby preciselydetermine the position of the cutting edge of insert 20. Each abutmentelement 26 is in the form of a knurled plug which will be seen inperspective in FIG. 4.

It is advantageous to form the plugs somewhat to a barrel shape withflat ends 30 and with the knurling 32 extending around the centralportion of the plug. Knurling 32 may advantageously be of the typeillustrated in FIG. 3 wherein it will be seen that the knurling isformed with peaks and valleys.

Axially aligned with abutment elements 26 in the shank portion 16 of theholder are threaded bores 34 having counter bores at one end, indicatedat 36. The threaded bores 34 and the counterbores 36 are adapted forreceiving adjustable abutment elements according to well knownpractices. What the present invention provides is the knurled plugsforming fixed abutment elements 26 which can be pressed into thecounterbores 36 so as to be fixedly held therein and which can be groundat their outer ends to provide for exactly the proper dimension X fromthe cutting edge of insert 20 to the wall of pocket 12 which the outerends of the knurled plugs, or abutment elements, engage.

Should it be desired, by the maker, or user, of the tool holder, toprovide for adjustable abutment elements, the knurled plugs can easilybe removed by running screws through the bores 34 from the ends oppositethe knurled plugs and forcing the knurled plugs out. Thereafter,conventional threaded abutment screws can be threaded into bores 34 withthe heads of the screws at the counterbored ends of the bores and aconventional adjustable abutment tool holder of the type illustratedwill be provided. Similarly, a tool holder of the type illustratedhaving adjustable abutment screws in bores 34 can be converted to a toolholder having a precise fixed X dimensions by removing the screws frombores 34, pressing knurled plugs into the counter bores 36, and thengrinding the knurled plugs to the proper dimension.

It will be evident that the arrangement of the present invention is notonly of substantial benefit to the manufacturer of the holders, but itis also of substantial benefit to the manufacturer of the machine toolsand to the users of the holders by substantially reducing inventoriesrequired,-while permitting the holders readily to be converted from thetype in which the X dimension is adjustable to the type in which the Xdimension is fixed.

The adjustable abutment screw 28 is usually retained but it is alsopossible for this screw to be replaced by a fixed abutment element. Suchan arrangement is illustrated in FIG. 5 which shows the extreme left endof the shank portion 16 of a tool holder. The shank portion 16 isprovided with the threaded axial bore 40 adapted for receiving theadjustable abutment screw 28 which, in FIG. 5, is replaced by apressed-in abutment element 42 which has an end part 44 of a size to bepress fitted into the threads of bore 40 while having a step 46 formedon the shank side of head 42. When abutment element 42 is pressed inplace, it can then be ground to a precise dimension and therebyprecisely determine the dimension from the back end of pocket 12 to theouter tip of the cutting insert.

The step 46 permits the introduction of a prying tool under the head ofthe abutment element 42 so that it can be pried out of threaded bore 40.The fit of portion 44 in threaded bore 40 is such that, while thethreads of the bore are deformed to the extent necessary to grip theabutment element when it is pressed into bore 40, after the abutmentelement is pried out of the bore, a screw can still be forced into thebore.

Alternatively, the threads of bore 40 deformed by the pressed inabutment element can be cleaned up with a tap. Still further, the bore40 could be provided with a counterbored outer end and the abutmentelement 42 provided with a knurled portion pressed into the counterborein the same manner as the abutment elements 26 are pressed into thecounterbores 36.

As in the case with the abutment elements 26, the abutment element atthe back end of the holder can either be of the adjustable type or afixed ground type whereby the holders can be readily converted from theadjustable type to the fixed type.

What is claimed is:

1. in a tool holder; a shank having means to support a cutting elementat one end, said shank being receivable in a support and being adaptedfor being fixedly clamped to the support, said support having at leasttwo angu arly related walls which respectively ace one side of saidshank and the end of said shank opposite the said one end thereof, boresin said shank to receive abutment elements which protrude from saidbores for engagement with said walls of said support to locate said toolholder relative to the support, said bores having at least a portion ofthe length thereof threaded, and abutment elements receivable in saidbores and including screw threaded first abutment elements adapted foradjustable threaded engagement with the threaded portions of said boresand second abutment elements adapted for being press fitted in saidbores, said bores being distributed along the length of said one side ofsaid shank and the said end of the shank 0pposite said one end thereof,said shank and each of said second abutment elements comprisingcooperating elements of interengaging abutment means for fixedlylocating said second abutment elements relative to the said shank whenpress fitted in the respective said bores.

2. A tool holder according to claim 1 in which at least some of saidbores are provided with counterbored ends in which the respective secondabutment elements are pressed, and the shoulders at the bottom of thecounterbores in said bores and the inner ends of said second abutmentelements forming said cooperating elements of interengaging abutmentmeans.

3. A tool holder according to claim 1 in which at least one of saidbores is threaded completely to the end thereof in which the respectivesecond abutment element is mounted and the pertaining said secondabutment element is adapted for being pressed into the bore whiledeforming the threads in the bore and includes a shoulder facing saidshank and engageable with the side of said shank adjacent the respectivebore to locate the said second abutment element on the shank, saidshoulder and said side of the shank adjacent said bore forming saidcooperating elements of interengaging abutment means.

4. A tool holder according to claim 2 in which at least the said secondabutment elements in said counterbored ends of said bores are in theform of cylindrical button members having knurled peripheries.

5. A tool holder according to claim 3 in which the said second abutmentelement includes a further shoulder spaced axially outwardly from thefirst mentioned shoulder for engagement by a prying tool to remove theabutment element from the bore.

6. A tool holder according to claim 1 in which said shank is bar-likeand at least two of said bores are disposed in spaced relation alongsaid one side of said shank and extend completely through the shank inthe lateral direction thereof.

1. In a tool holder; a shank having means to support a cutting elementat one end, said shank being receivable in a support and being adaptedfor being fixedly clamped to the support, said support having at leasttwo angularly related walls which respectively face one side of saidshank and the end of said shank opposite the said one end thereof, boresin said shank to receive abutment elements which protrude from saidbores for engagement with said walls of said support to locate said toolholder relative to the support, said bores having at least a portion ofthe length thereof threaded, and abutment elements receivable in saidbores and including screw threaded first abutment elements adapted foradjustable threaded engagement with the threaded portions of said boresand second abutment elements adapted for being press fitted in saidbores, said bores being distributed along the length of said one side ofsaid shank and the said end of the shank opposite said one end thereof,said shank and each of said second abutment elements comprisingcooperating elements of interengaging abutment means for fixedlylocating said second abutment elements relative To the said shank whenpress fitted in the respective said bores.
 2. A tool holder according toclaim 1 in which at least some of said bores are provided withcounterbored ends in which the respective second abutment elements arepressed, and the shoulders at the bottom of the counterbores in saidbores and the inner ends of said second abutment elements forming saidcooperating elements of interengaging abutment means.
 3. A tool holderaccording to claim 1 in which at least one of said bores is threadedcompletely to the end thereof in which the respective second abutmentelement is mounted and the pertaining said second abutment element isadapted for being pressed into the bore while deforming the threads inthe bore and includes a shoulder facing said shank and engageable withthe side of said shank adjacent the respective bore to locate the saidsecond abutment element on the shank, said shoulder and said side of theshank adjacent said bore forming said cooperating elements ofinterengaging abutment means.
 4. A tool holder according to claim 2 inwhich at least the said second abutment elements in said counterboredends of said bores are in the form of cylindrical button members havingknurled peripheries.
 5. A tool holder according to claim 3 in which thesaid second abutment element includes a further shoulder spaced axiallyoutwardly from the first mentioned shoulder for engagement by a pryingtool to remove the abutment element from the bore.
 6. A tool holderaccording to claim 1 in which said shank is bar-like and at least two ofsaid bores are disposed in spaced relation along said one side of saidshank and extend completely through the shank in the lateral directionthereof.